>>43070970My favorite route would probably be Route 104 from Ruby & Sapphire since it felt like taking my first steps on my own into the game without any of the handholding in previous routes as well as having the ocean, a small lake to the northern end and the Petalburg woods smack dab in the middle of it. Also the music was pretty darn nice and makes me feel nostalgic whenever I hear it.
https://youtu.be/Cc_etNphqkUCould have a Wobbuffet relaxing on the beach or building a sandcastle on the southern portion as a suggestion.